In projection systems used in vehicle simulator systems of the prior art, a user is seated enclosed in a set of screens or inside a spherical screen that surround the user and provide him with a field of view comparable to that in a real aircraft or other vehicle being simulated. In such systems, generally referred to as domes, usually several projectors are supported outside the surrounding screen structure.
Each projector projects a moving real-time image through an aperture in the screen structure to display a respective moving image that represents a part of the complete out-the-window view displayed to the user of the simulator. Several types of projectors can be used in this system, including scanning laser projectors. These scanning laser projectors each have a single laser beam that is modulated and caused to scan at very high speed through a projected image field so as to project or “paint” the image on the screen.
One concern associated with projectors, and especially laser projectors, is that laser light used in the projection is extremely bright. It is generally recognized as undesirable that this bright laser light be shone directly into the eye of the user, and that it should be viewed only reflected on a projection screen surface. Existing systems do not provide cost efficient systems of doing this with full reliability.
Another problem encountered is that, due to the imperfect nature of real-world optics, the surface of the last lens of the lens system of the projector virtually inevitably scatters part of the light passing therethrough. Since this lens surface is just outside the aperture through which the projector shines the image into the projection sphere, the user can look through the aperture and see the lens surface and the scattered light as a bright spot of light in the field of view. These bright spots at each of the projector apertures detract from the realism of the display, especially where the out-the window scene is of reduced light intensity, such as in a simulation of a night environment.